I am interested in learning more about microvascular complications (especially kidney) in kids under age 7 diagnosed with Type 1 diabetes. Is it true that until after puberty that these complications don't really seem to kick-in for the kids? After puberty, what percentage of the children will go on to develop these complications?

If I read the DCCT notes correctly, these complications can be either significantly (>80%) reduced or averted if stringent control is maintained. What exactly is acceptable control for children (e.g., blood glucose in the range of 80-180, or should it be even tighter still)?

I have a friend of a friend (who is Type 1) who was in the hospital during the last 6 months of her pregnancy due to her diabetes and is now in kidney distress that was attributed to the pregnancy. Does being pregnant really affect diabetics that drastically or do you suppose there was some underlying cause for her problems. She is now 45 and gave birth 12 years ago and has been diabetic since youth.

Answer:

The
DCCT study
did show that strict control of the blood sugar can
decrease the risk of early complications. The study was not carried out
long enough to prove if or how much strict control could decrease the
risk of late, severe complications such as blindness or kidney failure,
though it seems reasonable to assume that strict control will help
prevent or delay these more serious complications.

In the initial report "The effect of intensive treatment of diabetes on
the development and progression of long-term complications in
insulin-dependent diabetes mellitus" in the New England Journal of
Medicine, September 30, 1993, volume 329, pages 977-86, the development
of complications was expressed as "rate of event per 100 patient
years." ("Patient years" is the number of patients followed
multiplied by the number of years they are followed. "100 patient
years" can equal 100 patients followed for 1 year, or 50 patients followed
for 2 years, 25 patients followed for 2 years plus 50 patients followed
for 1 year, 10 patients followed for 4 years, 10 patients followed for 3
years, 10 patients followed for 2 years, plus 10 patients followed for 1
year, and so on.) There were 1441 patients in the DCCT study followed
from 3 to 9 years.

In this study, retinopathy first appeared at a rate of 4.7 patients per
100 patients years in the "intensive" or strict control treatment group
vs 1.2 patients per 100 patient years in the "conventional" or loose
control group. This represented a 76% risk reduction. In patients who
had early retinopathy at the start of the study, it progressed at a rate
of 7.8 patients per 100 patient years in the "intensive" or strict
control group vs 3.7 patients per 100 patient years in the
"conventional" or loose control group. This represented a 54% risk
reduction.

The appearance of abnormal albumen excretion > 300 mg/24 hr (early
kidney disease, but not kidney failure) was 0.3 vs. 0.2 patients per 100
patient years (intensive vs conventional) in those patients who had no
eye disease and 1.4 vs 0.6 patients per 100 patient years in those
patients who had early eye disease at the beginning of the study. This
represented a 44% and 56% reduction of kidney disease.

The question whether or not prepubertal children are protected from the
risk of high blood sugar until they enter puberty is still being
argued. There probably is some protection prior to puberty as it is
extremely rare to develop complications until at least 5 years after the
onset of puberty.

It is really very difficult in my opinion to quantitate the long term
risk of severe complications such as blindness and kidney failure as
these complications do not usually occur until at least 10 years after
the onset of puberty (the DCCT study wasn't carried out long enough to
assess the risk with intensive control). I think it is important to
remember that most statistics describing the risk of long term
complications were derived before the long term use of home blood
glucose monitoring. If detected early, both eye disease and kidney
disease can often be successfully treated to prevent or delay the more
severe problems.

Finally, it is unlikely that pregnancy caused the kidney problems in
your friend. If kidney problems are present before the onset of
pregnancy they may become worse during pregnancy. It does not seem
however that pregnancy itself increases the risk of later kidney
disease.

Last Updated: Tuesday April 06, 2010 15:08:54
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